1. Field of the Invention
Aspects of the present invention relate to a deposition mask.
2. Description of the Related Art
Among various methods of forming a thin film of a display device, a method of forming a thin film pattern, by depositing a target material using a mask, is commonly used. Common deposition using a mask is performed by aligning a mask on a deposition substrate, for example, a substrate of a display device, and applying a target material to the deposition substrate, through the mask, to form a thin film having a desired pattern on the deposition substrate.
A mask includes a frame and a mask sheet fixed to the frame and having a predetermined pattern. Generally, the frame has a predetermined thickness, a square shape, and an opening formed its center. An edge of the mask sheet is in contact with, and fixed to, the frame, thereby forming the mask.
The mask formed as such is stacked onto a deposition substrate, and a thin film is formed by depositing a target material on the deposition substrate. The thin film has a pattern that corresponds to a pattern formed on the mask sheet. Thus, for fine deposition, the mask may be closely adhered to the deposition substrate.
However, contaminants may be inserted between the mask frame and the mask sheet, while forming or using the mask. Such contamination may prevent the mask from being properly positioned on the deposition substrate. That is, when the mask is stacked on the deposition substrate, the contamination forms a gap between the mask and the deposition substrate. Due to the gap, the patterning of the thin film is disrupted, due to the generation of a shadow during patterning, which results in defects.